High energy rechargeable lithium batteries would be of great importance for the entire field of heart pump development. Future progress in this area is shown to depend on successful development of a lithium electrode (anode) with desirable rechargeability characteristics. The basic criteria for rechargeability of lithium anodes are discussed as well as the electrocrystallization process of whisker growth and the morphological leveling mechanism. Following considerations of solvent systems, their potential stability "windows" and of other properties, several new electrolyte systems are selected for Phase I study to improve electrocrystallization on the lithium anode and avoid dendrite formation. The proposed program consists of 2 technical tasks and a final report preparation. This program is expected to provide a new basis for identifying promising approaches to electrolyte systems which are stable and conducive to an understanding of the factors for the extended cycling capability of lithium anodes in secondary ambient temperature batteries. The Phase I program will serve to establish basic new lines of approach, so that in Phase II the System can be optimized and integrated with other components of rechargeable high energy lithium batteries for percutaneous or transcutaneous energy transmission applications.